From YouTube: "The Best HD Truck for Work and Play" You'll have 2 options for the HD trucks: a 6.6L Gas and a 6.6L Diesel engine. The gas engine is perfect for those who do light towing and need this truck for short trips, daily driving in the city, etc. The Duramax engine is perfect for those who do heavy-duty towing on the regular, those with long commutes, and who tow often. The diesel engine provides more power and torque to help you get the job done comfortably. #GMC #gmctrucks #gmcsierra #HDTruck #towing #trucks #s#stlouis